Pressure-retaining valve.



G. O. HAMMOND.

PRESSURE RETAINING VALVE.

APPLICATION FILED MAR.21,1911.

1,026,31 1 Patented May 14, 1912.

i 30 j j if 6 l "I 21 J f 1 7 COLUMBIA PLANOGRAPH ISO-.WASHINGTON, 1.:vc4

UNITED STATES OFFICE.

GEORGE O. HAMMOND, OF WATER/DOWN, NEW YORK, ASSIGNOR TO THE NEW YORK AIRBRAKE COMPANY, A CORPORATION OF NEW JERSEY.

PRESSURE-RETAINING VALVE.

To all whom it may concern Be it known that I, Gnonon O. HAMMOND, acitizen of the United States, residing in WVatertown, in the county ofJefferson and State of New York, have invented an Improvement inPressure-Retaining Valves, of which the following description, inconnection with the accompanying drawings, is a specification, likenumerals on the drawings representing like parts.

The present invention relates to a pressure retaining device of thatclass which is used in connection with an automatic air brake system inwhich it is desirable to retain pressure in the brake cylinders incertain cars of the train; and, in cases where a train is made up ofempty and loaded cars, to retain a greater pressure in the brakecylinders of the heavier loaded cars than in those of the empty orlighter cars.

The invention is shown as embodied in a valve having a three-way cockprovided with an inlet cavity in communication with the triple valveexhaust in all positions, the said cavity being adapted to communicate,respectively, with an open exhaust port and two supplemental exhaustports controlled respectively by loaded valves to retain differentpressures, the movement of the three-Way cock selectively controllingthese ports.

The separate pressure retaining valves, in accordance with theinvention, are controlled by a weight or equivalent load so arrangedthat more pressure is required to overcome the load on one valve than isre quired to overcome the load on the other, and the said weight, whichacts on both valves, is shown as resting on a yoke 01' lever which issupported at two points directly upon the valves, respectively, whilethe weight bears on the yoke at a point between the valves. This yoke,when either port is in communication with the exhaust from the triplevalve, so that the retaining valve controlling said port is lifted, iscapable of operating as a lever having its fulcrum on the other valve,the weight hearing down upon the lever to close the valve when thepressure in the brake cylinder has been reduced to the desired extent.

Figure l is a vertical section, through a pressure retaining valveembodying the invention, the controlling plug valve or three-way cockbeing shown in elevation Specification of Letters Patent.

Application filed March 21, 1911.

Patented May 1 1, 1912.

Serial No. 615,933.

with the ports in dotted lines; Fig. 2 is a partial view of the cockshowing the same in the high pressure retaining position; Fig. 3 is asimilar view showing the cock in the low pressure retaining position;and Fig. =1: is an end View of the cock showing the cavity and ports indotted lines.

In Fig. 1, the pressi'ire-retaining valve is shown as in its normalposition, that is to say, the position in which it performs no functionin the operation of the brakes, the cock being set so that the cavity 2receives air from the triple valve exhaust port 3, and permits the airto escape through an open port at in the valve shell or casing If it isdesired to retain excess pressure, the cock is turned by means of thehandle (3 to one of 'two positions, in both of which positions the openport t is closed, and the exhaust from the brake cylinder delivered toone or the other of the ports 7 and 8. All conmumication with theseports is through a longitudinal pocket or port 9 in the cock 1, the saidcock having an inlet passage 10 from the cavity 2 and outlet ports 12and 13 radial to the axis of the cock, and at an angle to each other, asshown; the outlet 12 opening communication with the high pressure duct 7when the handle 6 is .in one position, and the outlet 13 openingcon'nnunication with the low pressure duct 8 when the handle is inanother position. The ducts 7 and 8 are provided with final outletscontrolled by valves 14 and 15, which are shown as of different areas,so that more pressure is required to lift one than is required to liftthe other, and both of the said valves are loaded by means of a singleweight 16, which is supported by said valves at different points. Thesaid weight 16 is contained in the casing 17 intowhich the ports open,and the said casing is provided with an exhaust opening 18. The weightis herein shown as arranged to bear down on an interposed yoke or lever19 which in turn bears upon both of the valves 14: and 15. The weight isprovided with a knife edge or pointed bearing 20 which rests in adepressed portion 21. of the yoke located between the knife edge orpointed bearings 22 and 23 which rest in concave depressions formed inthe tops of the valves 14 and 15. WVhen, therefore, either one of theports 7 or 8 is put into communication with the brake cylinder exhaust,the valve controlling the said port will be lifted, moving the yoke 19upward with its bearing on the other valve as the fulcrum or pivotalsupport, the weight-1.6 being lifted, but acting to close whichever portis in communica tion with the exhaust as soon as the pressure exerted bythe weight is in excess of the effectual brake cylinder exhaust pressureact-ing on the valve. In the construction shown, the different areas ofthe valves subjected to the pressure are directly proportional to thepressure to be retained, and the weight is shown as having its center ofgravity substantially over a point midway between the valves. It isobvious, however, that this specific arrangement might be modified, anda change in leverage depended upon instead of, or in addition to, thedifferent pressure areas.

To retain the higher pressure, the handle 6 is moved to such a positionas to bring the port 12 into communication with the port 7, so that thebrake cylinder exhaust will be cont-rolled by the valve 14 of smallerarea, and for the low pressure retaining position, the handle 6 is movedto such a position that the exhaust from the brake cylinder through theport 13 and the port 8 will be controlled by the valve 15 of largerarea. The three positions of the handle are indicated by lines in Fig.4, the high pressure retaining position being indicated by the lettersHP, the

- low pressure retaining position being indicated by the letters LP, andthe normal or free exhaust position being indicated by the letter N. Theyoke 19 is loosely hung upon the valves 14 and 15, and is prevented fromjarring out of position by means of guide pins 2 1. and 25 which aresecured in the upper part of the main valve casing 5 and extend throughopenings in the ends of the yoke.

The construction is extremely simple, and both the high and low pressureretaining ports are direct, so that there is very little opportunity forleakage of any kind, and the means for supporting the weight are suchthat substantially no friction is encountered in the operation of thevalves, the amount of pressure retained, therefore, being directly inproportion to the weight and its actual effect on the valve controllingthe ort.

What I claim is:

1. In a pressure retaining valve, a brake cylinder exhaust port;automatic valves controlling communication with said exhaust port, saidvalves having different areas subjected to the pressure of the escapingair; means for causing the escaping air to act on said valvesselectively; a weight adapted to act on both the said valves; and asupport for said weight interposed between the weight and the valves,and resting directly on the said valves.

2. In a pressure retaining valve, a con trolling member consisting of athree-way cock interposed between the brake cylinder exhaust and thepressure retaining valve; a direct outlet adapted to be opened when thesaid three-Way cock is in one position; ducts controlled by saidthree-Way cock in addition to said direct outlet; supplemental valvescontrolling said ducts and having different areas subjected to pressure;a weight arranged to act on both the said valves; and a yoke supportedat one end on one of said valves, and at the other end on the other ofsaid valves, the weight resting on the yoke at a point betweenthe'valves.

3. In a pressure retaining valve, the combination with a cock adapted tocontrol selectively a plurality of ports; of valves controlling two ofsaid ports; a yoke or lever engaging said valves and tending to holdthem seated; and a weight bearing on said yoke at a point between theparts which engage the valves.

4:. A pressure retaining device comprising automatic valves controllingseparate ports leading from a source of pressure, said valves differlng1n the area exposed to the pressure; a load common to both valves and.

adapted to act on either valve which is subjected to pressure; and meansfor causing the pressure to act on said valves selectively. In testimonywhereof, I have signed my name to this specification in the presence oftwo subscribing witnesses.

' GEORGE O. HAMMOND. Vitnesses JNo. F. MALONEY, WV. F. NIooL.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. G.

